Book Numbers

In the US each year, between 25,000 and 35,000 new children's books are published.

I just came across this interesting fact in The Story of English by Robert McCrum, William Cran and Robert MacNeil:

Before 1500 the total number of books printed throughout Europe was about 35,000, most of them in Latin.

We've come a long way in five hundred years when a single year's number of new titles just for children in a single country amounts to the accumulated number of titles for an entire continent.